Ready NAS duo (RND2150v2) dead. Disks seems to be ok but where do I find the content?

You didn't mention what you are using to access the file system outside the NAS.  But did you look in C?  That's where the shares should be located.  But it is possible that the volume was corrupted by whatever made your NAS unavailable or is the cause of that unavailability.

In what way is your NAS "Dead"?  Other than remove the drives to try to access the content, have you done any troubleshooting?

You say that your NAS is a RND2150V2.  That is likely what we actually refer to as a V1 here, as I don't believe the true V2 ever was sold with drives (and would thus have the 2150 designation of shipping with one 500GB drive).  Ignore and label of the back or bottom of the NAS.  Netgear used the "V2" designation to mean two different things at different phases of production.  The true V2 says so on the front, and it also has a fan that's the full width of the case.  It is important that you know which it is, as forward steps may be different based on that.